1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 #pragma ident "%Z%%M% %I% %E% SMI"
27
28 /*
29 * Copyright (c) 2003 Constantin S. Svintsoff <kostik@iclub.nsu.ru>
30 *
31 * Redistribution and use in source and binary forms, with or without
32 * modification, are permitted provided that the following conditions
33 * are met:
34 * 1. Redistributions of source code must retain the above copyright
35 * notice, this list of conditions and the following disclaimer.
36 * 2. Redistributions in binary form must reproduce the above copyright
37 * notice, this list of conditions and the following disclaimer in the
38 * documentation and/or other materials provided with the distribution.
39 * 3. The names of the authors may not be used to endorse or promote
40 * products derived from this software without specific prior written
41 * permission.
42 *
43 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
44 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
45 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
46 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
47 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
48 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
49 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
50 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
51 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
52 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
53 * SUCH DAMAGE.
54 */
55 /*
56 * http://www.openbsd.org/cgi-bin/cvsweb/src/lib/libc/stdlib/realpath.c
57 * $OpenBSD: realpath.c,v 1.13 2005/08/08 08:05:37 espie Exp $
58 */
59
60 #include <stdio.h>
61 #include <unistd.h>
62 #include <string.h>
63 #include <limits.h>
64 #include <errno.h>
65 #include <sys/types.h>
66 #include <sys/stat.h>
67 #include <sys/param.h>
68
69 /*
70 * char *s_realpath(const char *path, char resolved_path[MAXPATHLEN]);
71 *
72 * Find the real name of path, by removing all ".", ".." and symlink
73 * components. Returns (resolved) on success, or (NULL) on failure,
74 * in which case the path which caused trouble is left in (resolved).
75 *
76 * DEVINFO: For libdevinfo we have added code to special case symlinks into
77 * /devices - the path below that point is known to not point to any
78 * additional symlinks. This knowledge allows us to avoid causing attach.
79 */
80 char *
s_realpath(const char * path,char * resolved)81 s_realpath(const char *path, char *resolved)
82 {
83 struct stat sb;
84 char *p, *q, *s;
85 size_t left_len, resolved_len;
86 unsigned symlinks;
87 int serrno, slen;
88 char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];
89
90 serrno = errno;
91 symlinks = 0;
92 if (path[0] == '/') {
93 resolved[0] = '/';
94 resolved[1] = '\0';
95 if (path[1] == '\0')
96 return (resolved);
97 resolved_len = 1;
98 left_len = strlcpy(left, path + 1, sizeof (left));
99 } else {
100 if (getcwd(resolved, PATH_MAX) == NULL) {
101 (void) strlcpy(resolved, ".", PATH_MAX);
102 return (NULL);
103 }
104 resolved_len = strlen(resolved);
105 left_len = strlcpy(left, path, sizeof (left));
106 }
107 if (left_len >= sizeof (left) || resolved_len >= PATH_MAX) {
108 errno = ENAMETOOLONG;
109 return (NULL);
110 }
111
112 /*
113 * Iterate over path components in `left'.
114 */
115 while (left_len != 0) {
116 /*
117 * Extract the next path component and adjust `left'
118 * and its length.
119 */
120 p = strchr(left, '/');
121 s = p ? p : left + left_len;
122 if (s - left >= sizeof (next_token)) {
123 errno = ENAMETOOLONG;
124 return (NULL);
125 }
126 (void) memcpy(next_token, left, s - left);
127 next_token[s - left] = '\0';
128 left_len -= s - left;
129 if (p != NULL)
130 (void) memmove(left, s + 1, left_len + 1);
131 if (resolved[resolved_len - 1] != '/') {
132 if (resolved_len + 1 >= PATH_MAX) {
133 errno = ENAMETOOLONG;
134 return (NULL);
135 }
136 resolved[resolved_len++] = '/';
137 resolved[resolved_len] = '\0';
138 }
139 if (next_token[0] == '\0')
140 continue;
141 else if (strcmp(next_token, ".") == 0)
142 continue;
143 else if (strcmp(next_token, "..") == 0) {
144 /*
145 * Strip the last path component except when we have
146 * single "/"
147 */
148 if (resolved_len > 1) {
149 resolved[resolved_len - 1] = '\0';
150 q = strrchr(resolved, '/') + 1;
151 *q = '\0';
152 resolved_len = q - resolved;
153 }
154 continue;
155 }
156
157 /*
158 * Append the next path component and lstat() it. If
159 * lstat() fails we still can return successfully if
160 * there are no more path components left.
161 */
162 resolved_len = strlcat(resolved, next_token, PATH_MAX);
163 if (resolved_len >= PATH_MAX) {
164 errno = ENAMETOOLONG;
165 return (NULL);
166 }
167
168 /*
169 * DEVINFO: Check if link points into /devices and resolve
170 * without causing attach if that is the case - there are no
171 * further symlinks in /devices.
172 */
173 if (strcmp(resolved, "/devices") == 0) {
174 resolved[resolved_len] = '/';
175 resolved_len = strlcat(resolved, left, sizeof (left));
176 left_len = 0;
177 continue;
178 }
179
180 if (lstat(resolved, &sb) != 0) {
181 if (errno == ENOENT && p == NULL) {
182 errno = serrno;
183 return (resolved);
184 }
185 return (NULL);
186 }
187
188 if (S_ISLNK(sb.st_mode)) {
189 if (symlinks++ > MAXSYMLINKS) {
190 errno = ELOOP;
191 return (NULL);
192 }
193 slen = readlink(resolved, symlink,
194 sizeof (symlink) - 1);
195 if (slen < 0)
196 return (NULL);
197 symlink[slen] = '\0';
198
199 if (symlink[0] == '/') {
200 resolved[1] = 0;
201 resolved_len = 1;
202 } else if (resolved_len > 1) {
203 /* Strip the last path component. */
204 resolved[resolved_len - 1] = '\0';
205 q = strrchr(resolved, '/') + 1;
206 *q = '\0';
207 resolved_len = q - resolved;
208 }
209
210 /*
211 * If there are any path components left, then
212 * append them to symlink. The result is placed
213 * in `left'.
214 */
215 if (p != NULL) {
216 if (symlink[slen - 1] != '/') {
217 if (slen + 1 >= sizeof (symlink)) {
218 errno = ENAMETOOLONG;
219 return (NULL);
220 }
221 symlink[slen] = '/';
222 symlink[slen + 1] = 0;
223 }
224 left_len = strlcat(symlink, left,
225 sizeof (left));
226 if (left_len >= sizeof (left)) {
227 errno = ENAMETOOLONG;
228 return (NULL);
229 }
230 }
231 left_len = strlcpy(left, symlink, sizeof (left));
232 }
233 }
234
235 /*
236 * Remove trailing slash except when the resolved pathname
237 * is a single "/".
238 */
239 if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
240 resolved[resolved_len - 1] = '\0';
241 return (resolved);
242 }
243